In a conventional vehicle antitheft system, a bar code is provided in a key, and starting of the engine of the vehicle is permitted only when the bar code matches a registered code which has been stored in advance in the vehicle antitheft device (Japanese Patent Application Laid-Open No. 62-88644).
Registered codes are stored in advance in the vehicle antitheft system when the vehicle is shipped from the factory. In this vehicle antitheft system, in a case in which a key is lost or in a case in which a key is stolen or the like, it is necessary to make possible the starting of the engine of the vehicle by using a new key. In order to do so, by using a tool used exclusively for such a purpose and a pass code, the registered code which has already been registered must be erased, and an identification code corresponding to a new key must be registered. Further, in cases in which other keys are also to be used, identification codes corresponding to these new keys must be registered.
However, in the conventional vehicle antitheft system, the tool used exclusively for such a purpose is needed in order to register a new code, re-register a code, or erase a registered code. Therefore, it is either necessary to take the vehicle into the service dealer or bring the tool used exclusively for such a purpose to the location of the vehicle in order to effect erasure and registration. There is a problem in that the erasure of codes stored in advance and the re-registration of new identification codes require much trouble.
Further, there is a problem in that erasure of codes and re-registration of codes cannot be carried out if the pass number has been forgotten.
The present invention was made in order to solve the above-described problems, and an object of the present invention is to provide a vehicle antitheft system and method in which erasure of registered codes, re-registration, and the like can be carried out without using a tool used exclusively for such purposes.